Telematics systems are becoming increasingly available in motor vehicles, with services such as automatic door unlocking in high demand. In one known method, telematics units partially deactivate, or enter discontinuous receive (DRX) mode, shortly after a vehicle's ignition is turned off. DRX mode places most subsystems and components in a telematics unit temporarily in a deactivated state for a period of time in order to preserve battery life. After the period of deactivation expires, the telematics unit is temporarily reactivated to check for incoming messages or service requests. After the reactivation period, the telematics unit returns to the deactivated state.
In a known system, when a vehicle is inactive for an extended period of time, such as, for example a number of days or weeks, the telematics unit enters a second or extended discontinuous receive mode. In the extended discontinuous receive mode the period of deactivation is increased and the period of activation is decreased or entirely suspended, with the intent of further preserving vehicle battery life.
Extended discontinuous receive mode becomes an inconvenience when a telematics subscriber requires an immediate service, such as an automatic door unlock request. Thus, a telematics subscriber may be required to wait up to thirty minutes or more for an automatic door unlock request to be successfully serviced by the telematics unit.